Walter’s two-layer hypothesis revisited: back to the roots!

Walter (Jahrb Wiss Bot 87:750–860, 1939) proposed a two-layer hypothesis, an equilibrium explanation for coexistence of savanna trees and grasses. This hypothesis relies on vertical niche partitioning and assumed that grasses are more water-use efficient than trees and use subsurface water while trees also have access to deeper water sources. Thus, in open savannas, grasses were predicted to predominate because of their water use efficiency and access to subsurface water. This hypothesis has been a prominent part of the savanna literature since first proposed. We review the literature on Walter’s hypothesis and reconsider his original intentions. Walter intended this hypothesis to be restricted to dry savannas. In his opinion, mesic and humid savannas were controlled by biotic factors and disturbances. We surveyed the global savanna literature for records of vertical niche partitioning by grasses and trees. We find that, within the scope of Walter’s original intentions, this hypothesis works remarkably well, and in some cases is appropriate for deserts as well as for dry temperate systems and even some mesic savannas.     

Signal through the noise? Phylogeny of the Tachinidae (Diptera) as inferred from morphological evidence

The oestroid family Tachinidae represents one of the most diverse lineages of insect parasitoids. Despite their broad distribution, diversity and important role as biological control agents, the phylogeny of this family remains poorly known. Here, we review the history of tachinid systematics and present the first quantitative phylogenetic analysis of the family based on morphological data. Cladistic analyses were conducted using 135 morphological characters from 492 species belonging to 180 tachinid genera, including the four currently recognized subfamilies (Dexiinae, Exoristinae, Phasiinae, Tachininae) and all major tribes. We used characters of eggs, first‐instar larvae and adults of both sexes. We examined the effects of implied weighting by reanalysing the data with varying concavity factors. Our analysis generally supports the subfamily groupings Dexiinae + Phasiinae and Tachininae + Exoristinae, with only the Exoristinae and the Phasiinae reconstructed as monophyletic assemblages under a wide range of weighting schemes. Under these conditions, the Dexiinae, which were previously considered a well‐established monophyletic assemblage, are reconstructed as being paraphyletic with respect to the Phasiinae. The Tachininae are reconstructed as a paraphyletic grade from which the monophyletic Exoristinae arose. The Exoristinae are reconstructed as a monophyletic lineage, but phylogenetic relationships within the subfamily are largely unresolved. We further explored the evolution of oviposition strategy and found that the oviparous groups are nested within ovolarviparous assemblages, suggesting that ovipary may have evolved several times independently from ovolarviparous ancestors. This counterintuitive pattern is a novel hypothesis suggested by the results of this analysis. Finally, two major patterns emerge when considering host associations across our phylogeny under equal weights: (i) although more than 60% of tachinids are parasitoids of Lepidoptera larvae, none of the basal clades is unambiguously associated with Lepidoptera as a primitive condition, suggesting that tachinids were slow to colonize these hosts, but then radiated extensively on them; and (ii) there is general agreement between host use and monophyly of the major lineages.     

Simple signaling games of sexual selection (Grafen’s revisited)

We investigate several versions of a simple game of sexual selection, to explore the role of secondary sexual characters (the “handicap paradox”) with the tools of signaling theory. Our models admit closed form solutions. They are very much inspired by Grafen’s (J Theor Biol 144:517–546, 1990a; J Theor Biol 144:473–516, 1990b) seminal companion papers. By merging and simplifying his two approaches, we identify a not so minor artifact in the seminal study. We propose an alternative model to start with Grafen’s sexual selection theory, with several similarities with Getty (Anim Behav 56:127–130, 1998).     

‘Candidatus Tisiphia’ is a widespread Rickettsiaceae symbiont in the mosquito Anopheles plumbeus (Diptera: Culicidae)

Symbiotic bacteria can alter host biology by providing protection from natural enemies, or alter reproduction or vectoral competence. Symbiont-linked control of vector-borne disease in Anopheles has been hampered by a lack of symbioses that can establish stable vertical transmission in the host. Previous screening found the symbiont ‘Candidatus Tisiphia’ in Anopheles plumbeus, an aggressive biter and potential secondary vector of malaria parasites and West Nile virus. We screened samples collected over 10-years across Germany and used climate databases to assess environmental influence on incidence. We observed a 95% infection rate, and that the frequency of infection did not fluctuate with broad environmental factors. Maternal inheritance is indicated by presence in the ovaries through FISH microscopy. Finally, we assembled a high-quality 1.6 Mbp draft genome of ‘Ca. Tisiphia’ to explore its phylogeny and potential metabolic competence. The infection is closely related to strains found in Culicoides biting midges and shows similar patterns of metabolism, providing no evidence of the capacity to synthesize B-vitamins. This infection offers avenues for onward research in anopheline mosquito symbioses. Additionally, it provides future opportunity to study the impact of ‘Ca. Tisiphia’ on natural and transinfected hosts, especially in relation to reproductive fitness and vectorial competence and capacity.     

Molecular pharming’s foot in the FDA’s door: Protalix’s trailblazing story

Objectives

This short commentary examines the factors that led to Food and Drug Administration’s approval of the first plant-derived biologic.

Results

In 2012, the first plant-derived protein pharmaceutical (biologic) was approved for commercial use in humans. The product, a recombinant form of human β-glucocerebrosidase marketed as ELELYSO, was developed by Protalix Biotherapeutics (Carmiel, Israel). The foresight to select this particular therapeutic product for development, flawless production pipeline, and serendipity seem to provide the key in explaining how ELELYSO became the first plant-derived biologic to achieve approval by Food and Drug Administration.

Conclusions

While the circumstances that enabled Protalix and its scientists to become the first to arrive at this historic milestone are perhaps unique, it is anticipated that more biologics will follow suit in winning regulatory endorsement.

     

Heterogeneity in shore flies – the case of Glenanthe Haliday (Diptera: Ephydridae) in the Old World

Old World species of the genus Glenanthe are treated comprehensively with an emphasis on the unusually diverse morphological heterogeneity discovered in structures of the male terminalia. As perspective for this treatment, the tribe Lipochaetini, in which Glenanthe is placed, is characterized and discussed, and an annotated key to the four included genera is provided to facilitate their identification. Glenanthe is demonstrated to be a monophyletic lineage within Lipochaetini. Seven Old World species of Glenanthe are now known, including two new Afrotropical species as follows (type locality in parenthesis): G. namibia n. sp. (Namibia. Mukwe: Divuju: Okavango River [18°04’04”S, 21°28’51”E] and G. danielssoni n. sp. (Republic of South Africa. Cape Province: De Hoop Nature Reserve [34°27’S, 28°25’E]. The identity of G. fuscinervis Becker, revised status (raised from synonymy with G. ripicola (Haliday)), is clarified, and found to be conspecific with Hydrina ochracea Oldenberg, which is recognized as a junior synonym. Papp’s synonymy of Glenanthe fasciventris Becker with Hydrellia (Glenanthe) ripicola Haliday is confirmed, and herein we relegate G. iranica Canzoneri & Rampini also as junior synonym of G. ripicola. The remarkable diverse structures of the male terminalia of all included species are described and illustrated and distribution maps are also provided.     

A new Microphorites in the Lower Cretaceous amber of the Southwest of France (Diptera: Dolichopodidae, “Microphorinae”)

A new deposit of Lower Cretaceous amber, found in Charente-Maritime (SW France) has yielded an important entomofauna with numerous arthropod associations characteristic of moist ground. We describe a new species of Dolichopodidae: ‘Microphorinae’(Diptera: Empidoidea), Microphorites deploegi n. sp. on the basis of seven male and female specimens of exceptional state of preservation. This genus was previously only known from Lebanese amber of the Lower Cretaceous. The present discovery supports a reconstruction of the palaeoenvironment as a sandy beach along the sea, under a warm climate.     

The Chironomidae and Ceratopogonidae (Diptera) of New Zealand’s subantarctic islands

Abstract

A taxonomic study of midges collected in the subantarctic islands of New Zealand yielded 22 species of Chironomidae and 4 of Ceratopogonidae. Only four of the chironomids occur elsewhere, three on ‘mainland’ New Zealand and one on The Snares islands. Of the 15 species found on the Auckland Islands, 11 on Campbell Island, and 5 on the Antipodes Islands, respectively 9, 4, and 2 are endemic. Nine new species are proposed in existing genera: Parochlus rennelli, P. reductus, P. gressitti, P. brevis, Telmatogeton antipodensis, Eukiefferiella heveli, Cricotopus aucklandensis, Chironomus antipodensis, and C. subantarcticus. Gressittius n.gen. is proposed for Corethra antarctica Hudson (type-species). Semiocladius n.gen. is proposed for Camptocladius crassipennis Skuse, and S. kuscheli n.sp. is described. Eight further new genera are proposed, with the following new species as type-species: Kuschelius dentifer, Mecaorus elongatus, Pterosis wisei, Hevelius carinatus, Gynnidocladius pilulus, Nesiocladius gressitti, Nakataia cisdentifer, and Maryella reducta. Genera Halirytus Eaton and Psamathiomya Deby are synonymised with Telmatogeton Schiner. Gressittius antarcticus (Hudson), Ablabesmyia mala (Hutton), Telmatogeton magellanicus (Jacobs), T. amphibius (Eaton), T. macquariensis (Brundin), Semiocladius crassipennis (Skuse), S. endocladiae (Tokunaga), and Calopsectra funebris (Freeman) are new combinations. Of the ceratopogonids, only one species occurs elsewhere in New Zealand. Three species, only one of them endemic, were found on the Auckland Islands; two were found on Campbell, of which only one is endemic. Forcipomyia kuscheli and Dasyhelea aucklandensis are proposed as new species.     

L-chromosome inheritance and the problem of chromosome “imprinting” in Sciara (Sciaridae,Diptera)

The loss of the L-chromosomes from the germ line of a newly-collected strain of Sciara impatiens was used as a genetic marker to test whether the supernumeraries in this genus obey the rule of origin which governs the behavior of the regular homologues at first meiotic anaphase in the male. Reciprocal crosses between a normal strain which possessed L's and the no-L line yielded F₁ males whose germ cells contained L-chromosomes of paternal or of maternal origin. Cytological study of the gonads of these males showed that in all instances, irrespective of their origin, the L-chromosomes were conserved. To demonstrate that the L's thus conserved are not lost subsequently during spermiogenesis, the F₁ males derived from normal fathers were bred to females from the no-L line; the gonads of the test-cross progeny showed that these individuals had inherited L-chromosomes. The failure of the paternal L's to obey the rule of origin during spermatogenesis indicates that the supernumeraries in this genus are not subject to the reversible imprinting which the regular complement undergoes. And the genetic effects of exclusively paternal or maternal L-chromosomes on germ cell development and maturation are indistinguishable. Concomitant with the loss of L's from the germ line, the newly-collected strain of S. impatiens underwent an abrupt alteration from unisexual families to variable sex ratios. These ratios are discussed in relation to the problem of sex determination in S. ocellaris, a species which sustained L-chromosome loss during the course of evolution. Discussed also are some new unpublished data which reveal, unexpectedly, a genetic affinity between ocellaris and impatiens. The no-L line of impatiens, which has been kept in laboratory culture for approximately four years, provides a unique opportunity to examine the conditions under which the supernumeraries are retained or lost and also to determine more precisely the nature of their genetic effects.It is a pleasure to acknowledge support by the National Science FoundationIt is a pleasure to acknowledge support by the National Science Foundation     

Landscape–Zonal Distribution of Blackflies (Diptera: Simuliidae) in the Ob-Irtysh River Basin (Overview)

The blackfly distribution patterns along the meridional profile for the Ob-Irtysh River basin area have been analyzed with the use of long-term quantitative data. Ninety-six species of nine genera, comprising approximately 60% of the fauna in Siberia and the Far East, are recorded. The spatial pattern formation in the blackfly zonal structures is revealed. There are significant differences between blackfly populations in highland and lowland landscapes. In the highlands, the communities confined to different altitudinal belts are formed. In the lowland of the basin, three community zonal types—steppe, taiga–forest, and tundra—are identified. Significant climatic factors affecting the heterogeneity of the blackflies in the Ob-Irtysh River basin have been estimated.     

A Neontologist’s review of two recently published articles on inclusions of Lestremiinae (Diptera: Cecidomyiidae) in Rovno amber

Two articles on fossil Lestremiinae (Diptera: Cecidomyiidae) in Rovno amber (Perkovsky and Fedotova, 2004; Fedotova and Perkovsky, 2004) are reviewed and discussed. As a result, the following gall midges species are considered Lestremiinae incertae sedis: + Aprionus admirandus Fed., + Conarete laesus Fed., + Heterogenella sparsa Fed., + Micromyia convoluta Fed., + Peromyia autonoma Fed., + Peromyia miranda Fed., + Peromyia sukachevae Fed., + Peromyia zherikhini Fed. (all in Perkovsky and Fedotova, 2004), + Campylomyza falciformis Fed., + Campylomyza superposita Fed., + Neurolyga declinata Fed., + Strobliella appropinquata Fed., and + Strobliella capitata Fed. (all in Fedotova and Perkovsky, 2004).     

Fruit‐breeding drosophilids (Diptera) in the Neotropics: playing the field and specialising in generalism?

1. Species of Drosophilidae are frequently used as model organisms, but their relationships with the environment, particularly in immature stages, remain poorly known. 2. This is the most comprehensive survey to date of fruit‐breeding drosophilids and their hosts in the Neotropics. Drosophilid host‐utilisation patterns were analysed as to geographic origin (native versus exotic) and level of specialisation. 3. The 180 species of plants recorded as drosophilid hosts are distributed across the main Angiosperm lineages and fleshy‐fruited orders; plant families that hosted the greatest number of drosophilid species were Arecaceae, Moraceae, and Myrtaceae. The 100 nominal drosophilid species recorded breeding in fruits belong to just over one‐third of Neotropical genera; most species (91) belong to Drosophila. Drosophilid species with the greatest resource breadth were Drosophila simulans, Drosophila nebulosa, and Zaprionus indianus. 4. Exotic drosophilids breed in more plant species than Neotropical drosophilids and use exotic hosts more frequently, possibly because they are generalists that have survived the trial of introduction and establishment in the Neotropics. Native drosophilids are more variable in resource breadth and sometimes adopt exotic hosts. 5. Amongst the 49 drosophilids with enough records for analysis (> 4), 48 were categorised as generalists. One possible explanation for such overwhelming generalism is the high diversity of Neotropical habitat or hosts. A second, non‐exclusive explanation, suggested by recent studies and empirically supported by the absence of host specialisation found in this study, is that drosophilids could be selective of the dominant yeasts and bacteria in host tissue, and not of the hosts themselves.     

Determination of phylogenetic position of Pipizini (Diptera: Syrphidae): based on molecular biological and morphological data

Based on the sequence analysis of 5.8S subunit and internal transcribed spacers (ITS ) of ribosomal RNA gene (rDNA), the molecular phylogenetic tree of representative species of Pipizini and three groups of Syrphidae with different feeding habits (seven species belong to six genera) was constructed. Meanwhile, the phylogenetic tree of tribes (including Pipizini and other 17 tribes of Syrphidae) was constructed using morphological characteristics of adults and larvae and the number of chromosomes. Both the results show that the relationship between Pipizini and predatory groups is closer than that between Pipizini and saprophagous groups. So it is suggested that Pipizini be transferred from Milesiinae to Syrphinae.     

Bloodsucking dipteran insects (Diptera) attacking humans and animals (the “gnus” complex) in northwestern Russia: I. General characteristics of the fauna

The fauna of bloodsucking Diptera of northwestern Russia comprises 226 species of mosquitoes (Culicidae), biting midges (Ceratopogonidae), black flies (Simuliidae) and horseflies (Tabanidae). In particular, Culicidae include 41 species from 10 subgenera of 5 genera of 2 subfamilies. Simuliidae are represented by 110 species of 23 genera, belonging to 6 tribes of 2 subfamilies; the genus Culicoides of the Ceratopogonidae, by 31 species; and Tabanidae, by 44 species of 7 genera from 2 subfamilies. There is a necessity of elaboration and application of more advanced forms of information storage and field data standardization. In the Zoological Institute, Russian Academy of Sciences, a special database on the bloodsucking insects of Russia is created in the DBMS Access. A list of abundant bloodsucking species of mosquitoes, biting midges, black flies and horseflies is included. A brief synopsis of bibliography of investigations of the bloodsucking dipterans from northwestern Russia is given, provided with a list of more then 190 publication.     

Tengmalm’s Owl (Aegolius funereus) (Strigidae,Aves) in the North Caucasus

Biology Bulletin - Abstract—Tengmalm’s Owl (Aegolius funereus caucasicus But.) inhabits dark coniferous, pine, and deciduous forests in the mountains of the North Caucasus in the range...